Memory leaks in version 0.9.x?

[mtymek]

Playing around with the library, I believe I found a memory leak. Here's a minimal application where I'm able to reproduce this issue:

<?php
namespace App;

use function Icicle\Awaitable\resolve;
use Icicle\Http\Message\{Request, Response};
use Icicle\Socket\Socket;
use Icicle\WebSocket\{Application, Connection};
use Icicle\Loop;

class EchoApplication implements Application
{
    public function __construct()
    {
        Loop\periodic(10, function () {
            $mem = round(memory_get_usage(false) / 1024) . 'k';
            $peak = round(memory_get_peak_usage(false) / 1024) . 'k';
            $date = date('H:i:s');
            echo "$date: mem: $mem, peak: $peak\n";
        });
    }

    public function onHandshake(Response $response, Request $request, Socket $socket)
    {
        return $response;
    }

    public function onConnection(Connection $connection, Response $response, Request $request)
    {
        yield $connection->send('Connected to echo WebSocket server powered by Icicle.');
        $iterator = $connection->read()->getIterator();

        while (yield $iterator->isValid()) {
            $message = $iterator->getCurrent();

            if ($message->getData() === 'close') {
                yield $connection->close();
            } else {
                yield $connection->send($message);
            }
        }
    }
}

This is simplified EchoApplication from attached example. Every 10 seconds It outputs current memory usage.

My test:

• run websocket server
• connect 1 client
• send 1 message from client
• wait, observe server output

Results:

With single connected client, every minute or so memory usage rises by a few kBs. After client is disconnected, I didn't observe it.

icicleio/websocket v0.9.5, XDebug enabled:

    [Info @ 2016/03/29 18:57:37] HTTP server listening on 0.0.0.0:8080
    [Debug @ 2016/03/29 18:57:41] Accepted client from 172.17.0.1:45434 on 172.17.0.2:8080
    [Debug @ 2016/03/29 18:57:41] Received request from 172.17.0.1:45434 for localhost:10011/?encoding=text
    [Debug @ 2016/03/29 18:57:41] Responded to request from 172.17.0.1:45434 for localhost:10011/?encoding=text with 101 Switching Protocols
    18:57:47: mem: 2492k, peak: 2743k
    18:57:57: mem: 2492k, peak: 2743k
    18:58:07: mem: 2492k, peak: 2743k
    18:58:17: mem: 2492k, peak: 2743k
    18:58:27: mem: 2492k, peak: 2743k
    18:58:37: mem: 2492k, peak: 2743k
    18:58:47: mem: 2507k, peak: 2758k
    18:58:57: mem: 2507k, peak: 2758k
    18:59:07: mem: 2507k, peak: 2758k
    18:59:17: mem: 2507k, peak: 2758k
    18:59:27: mem: 2507k, peak: 2758k
    18:59:37: mem: 2507k, peak: 2758k
    18:59:47: mem: 2517k, peak: 2767k
    18:59:57: mem: 2516k, peak: 2767k
    ...

icicleio/websocket v0.9.5, XDebug disabled:

    [Info @ 2016/03/29 19:00:50] HTTP server listening on 0.0.0.0:8080
    [Debug @ 2016/03/29 19:00:58] Accepted client from 172.17.0.1:45566 on 172.17.0.2:8080
    [Debug @ 2016/03/29 19:00:58] Received request from 172.17.0.1:45566 for localhost:10011/?encoding=text
    [Debug @ 2016/03/29 19:00:58] Responded to request from 172.17.0.1:45566 for localhost:10011/?encoding=text with 101 Switching Protocols
    19:01:00: mem: 2185k, peak: 2436k
    19:01:10: mem: 2186k, peak: 2436k
    19:01:20: mem: 2186k, peak: 2436k
    19:01:30: mem: 2186k, peak: 2436k
    19:01:40: mem: 2186k, peak: 2436k
    19:01:50: mem: 2186k, peak: 2436k
    19:02:00: mem: 2200k, peak: 2450k
    19:02:10: mem: 2199k, peak: 2450k
    19:02:20: mem: 2199k, peak: 2450k
    19:02:30: mem: 2199k, peak: 2450k
    19:02:40: mem: 2199k, peak: 2450k
    19:02:50: mem: 2199k, peak: 2450k
    19:03:00: mem: 2209k, peak: 2459k
    19:03:10: mem: 2208k, peak: 2459k
    19:03:20: mem: 2208k, peak: 2459k

What happens after disconnecting client:

[Debug @ 2016/03/29 20:20:47] Disconnected client from 172.17.0.1:36750 on 172.17.0.2:8080
20:20:48: mem: 2178k, peak: 2452k
20:20:58: mem: 2178k, peak: 2452k
20:21:08: mem: 2178k, peak: 2452k
20:21:18: mem: 2178k, peak: 2452k
20:21:28: mem: 2177k, peak: 2452k
20:21:38: mem: 2177k, peak: 2452k
20:21:48: mem: 2173k, peak: 2452k
20:21:58: mem: 2173k, peak: 2452k
20:22:08: mem: 2173k, peak: 2452k
20:22:18: mem: 2173k, peak: 2452k
20:22:28: mem: 2173k, peak: 2452k
20:22:38: mem: 2173k, peak: 2452k
...

Tests were done on PHP v7.0.4, running on Docker container.

This issue is not present when using master branch (dev-master 90fd48a of icicleio/websocket, dev-master 329068a of icicleio/icicle).

[trowski]

I will look into this. I'm also seeing the same behavior on master, so I'm wondering what might be going on. Any insight as to what might be being held in memory? Maybe something to do with observables?

[mister-good-deal]

PHP is less ennoying than C with the garbage collector but still requires a bit of attention with objects destruction.

Take a look at the first comment on this page it may help finding a part of code that avoid the garbage collector to work fine.